学生成绩管理系统

package dbconn; import java.sql.*; import java.lang.ClassNotFoundException; public class BaseConn { private Connection conn = null; private Statement stmt = null; private PreparedStatement ps = null; private ResultSet rs = null; public BaseConn() throws SQLException,ClassNotFoundException{ try { String url = "jdbc:mysql://localhost:3306/classmanage"; Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(url,"root","root"); }catch(SQLException e) { System.out.println("Error occured when Connect DataBase:"+e); throw e; } catch(ClassNotFoundException e) { System.out.println("Error occured when Connect DataBase:"+e); throw e; } } public PreparedStatement preparedStatement(String sql) throws SQLException { try { ps = conn.prepareStatement(sql); return ps; }catch(SQLException e) { System.out.println("Error occured when Connect DataBase:"+e); throw e; } } public static Connection getConnection() { String driverClass ="com.mysql.jdbc.Driver"; String url = "jdbc:mysql://localhost:3306/classmanage"; String userName = "root"; String password ="root"; System.out.println(driverClass + "\t" + url + "\t" + userName + "\t" + password); Connection conn = null; try { Class.forName(driverClass); conn = DriverManager.getConnection(url, userName, password); } catch (SQLException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } return conn; } /** * 执行静态 SQL 查询语句并返回它所生成结果的对象 * */ public ResultSet executeQuery(String sql) throws SQLException { rs = null; try { rs = stmt.executeQuery(sql); } catch (SQLException ex) { System.out.println("Error occured when query database：" + ex); throw ex; } return rs; } /** * 执行静态SQL更新语句并返回影响数据条数 * */ public int executeUpdate(String sql) throws SQLException { try { conn.setAutoCommit(false); int re = stmt.executeUpdate(sql); conn.commit(); return re; } catch (SQLException e) { conn.rollback(); System.out.println("Error occured when update database：" + e); throw e; } } /** * 执行预编译的SQL查询语句 * * */ public ResultSet executeQuery() throws SQLException { try { return ps.executeQuery(); } catch (SQLException e) { System.out.println("Error occured when query database：" + e); throw e; } } /** * 执行预编译的SQL更新语句 * * */ public int executeUpdate() throws SQLException { try { conn.setAutoCommit(false); int r = ps.executeUpdate(); conn.commit(); return r; } catch (SQLException e) { conn.rollback(); System.out.println("Error occured when update database：" + e); throw e; } } /** * 数据库关闭操作 * */ public boolean closeDB() throws SQLException { try { if (this.rs != null) rs.close(); if (this.stmt != null) this.stmt.close(); if (this.ps != null) this.ps.close(); if (this.conn != null) conn.close(); return true; } catch (SQLException e) { System.out.println("Error occured when close database：" + e); throw e; } } }